THERE is considerable debate in certain circles in the US over whether stem cells from adults will be as effective in treating disease as those from embryos. The White House, which opposes the use of human embryonic stem cells (ESCs) on ethical grounds, argues that we don鈥檛 need them since adult stem cells show great promise. This point has been central to the political discussions over whether to lift President George W. Bush鈥檚 restrictions on federal funding for research into human ESCs. The House of Representatives voted to lift them in January and the Senate will vote soon.
Among the majority of scientists, however, there is no debate at all. There is simply no substitute for the use of human ESCs if we are serious about delivering the medical advances that stem cells promise.
It has been clear for some time that therapies based on stem cells could transform healthcare. By injecting healthy replacement cells into damaged tissue, clinicians could restore function, perhaps permanently, to organs damaged by disease or injury. This approach goes far beyond what existing drugs or surgical techniques can achieve. Crucially, it would allow people to live free of illness for longer, resulting in lower long-term care costs, an important consideration in our ageing society.
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The concept of stem cell therapy is nothing new. Surgeons have been transplanting bone marrow, which contains stem cells, for 30 years. The procedure has saved or prolonged many lives. Yet, because bone marrow from one donor cannot be used in more than one recipient 鈥� it cannot be used to 鈥渕anufacture鈥� additional stem cells 鈥� the treatment is available only on a limited scale. This makes it expensive and means that the standard of delivery varies considerably among medical centres.
The difficulty of scaling up stem cell production is a fundamental reason for the pharmaceutical industry鈥檚 lack of interest in developing the technology. If a treatment cannot be mass-produced reliably, there is little financial incentive to invest in it.
There is a ready solution to this problem: human ESCs. One of the things that sets human ESCs apart from all adult stem cells discovered so far is that it is possible to increase their numbers using cell banks that have been standard in the biotechnology industry for years. This is because human ESCs continuously express the enzyme telomerase, which enables them to grow and replicate endlessly. For example, the human ESC master cell bank at my company is capable of generating enough therapeutic cells to treat every acute spinal cord injury in the US for the next 20 years 鈥� more than 250,000 patients. You cannot do this with adult stem cells.
Moreover, human ESCs are the only stems cells that are truly pluripotent 鈥� they are capable of turning into any type of cell in the body. This allows scientists to develop products that could treat many ailments.
Little wonder, then, that the scientific community in the US is frustrated by the current federal policy on human ESC research, which restricts funding to those few stem cell lines derived from embryos that were destroyed before 9 August 2001. Based on fundamentalist Christian beliefs and national politics instead of the potential impact on patients, the policy has severely limited the opportunities for the academic sector to work on human ESC-based therapies. The National Institutes of 91色情片 (NIH), which distributes almost $30 billion of public research funding each year, has reportedly spent just $130 million on human ESC research since 2001, compared with more than $2.8 billion on adult stem cells. Academia has been forced to seek support from scarce state and private sources, and its participation in human ESC research has become fragmented, uncoordinated and inefficient.
鈥淎cademia has been forced to seek support from scarce state and private sources鈥�
As a result, the technology is being advanced by biotechnology companies, private foundations and other governments. This is unprecedented. Consider how therapies derived from recombinant DNA, monoclonal antibodies and the products of the Human Genome Project evolved from NIH-funded academic research over many years, and how academia validated and improved on the initial discoveries long before the pharmaceutical industry took an interest in developing them. As a result of this research, treatments based on monoclonal antibodies and recombinant DNA for diseases such as rheumatoid arthritis, breast cancer and diabetes have become commonplace.
The former head of the NIH, Harold Varmus, has said that the impact of human ESC technology on medicine may far exceed that of the entire recombinant DNA industry. For this to happen, the constraints on federal funding must be lifted, allowing us to return to the traditional model of development based on a partnership between NIH-funded academic research and industrial investment. Failure to do this will delay cures for patients suffering debilitating diseases and erode the US鈥檚 global leadership in biomedical innovation.
